1. Field of the Invention
The present invention relates to scanning and detecting optical devices. More particularly, the invention is concerned with an apparatus which is capable of picking up an exact synchronizing signal.
2. Description of the Prior Art
Hitherto, it has been a common practice to pick up a synchronizing signal in image signals by means of a synchronizing signal detector which is arranged on a line of the scanning by light and which is separate from an image signal detector.
The above-described synchronizing signal detector essentially requires a photo-detector which is used exclusively for the purpose of detection of the synchronizing signal. When a magnifier lens is used, it is necessary to move the photo-detector each time the magnification is changed or to arrange a plurality of photo-detectors and to electrically switching them in accordance with the magnification. Thus, the conventional synchronizing signal detector is complicated in construction.